The main events that led to the Japanese attack on Pearl Harbor were actions that Japan took in pursuit of an empire in Asia and the Pacific. Added to this was the United States’ reaction to Japan’s actions. The combination of Japanese actions and US reaction led to the attack.

In the time after WWI, Japan wanted to expand its empire in its general region of the world. It wanted to be a major power with a large empire just like major European countries and the US. Japan started by closing off foreign access to its League of Nations mandate in Micronesia. This made the US worry that Japan was fortifying the islands and could use them to cut off American access to the Philippines (then a US territory) and the rest of Asia. Later, Japan invaded Manchuria and left the League of Nations when that organization ordered it to evacuate its new territory. After that, Japan invaded China. These invasions happened in the 1930s.

Finally, Japan occupied French Indochina in July of 1941. France had been defeated by Germany, which was Japan’s ally. Therefore, France could not really resist Japan’s occupation of Indochina. However, the Japanese occupation worried the US greatly. In response, the US cut off supplies of oil and scrap iron to Japan. This led to the attack on Pearl Harbor.